The present invention relates generally to a resin coated metal pipe for a lightweight structure which is manufactured by spreading adhesive on an outer surface of a thin metal pipe and coating synthetic resin on the adhesive so as to adhere the synthetic resin to the metal pipe and which is used as a raw material to construct a so called lightweight structure, such as a bench shown in FIG. 13, a flower stand shown in FIG. 3, a draining board shown in FIG. 9 or the like. More particularly, this invention relates to a resin coated metal pipe having a basically circular cross sectional shape and a plane surface for forming a flat surface for use in a lightweight structure.
A conventional resin coated metal pipe 1 for a lightweight structure, having a cross sectional shape as shown in FIG. 22, is manufactured by spreading adhesive 10 on an outer surface of a cold rolled steel pipe 2 having a circular shape and a thin thickness. In other words, the cross sectional shape of the conventional resin coated metal pipe 1 is circular. In the past, the resin coated metal pipe 1 was employed to construct a lightweight structure, such as a bench 4 shown in FIG. 23, a flower stand 5 shown in FIG. 24, a draining board 6 shown in FIG. 25 or the like.
As described hereinbefore by reference to FIG. 22, the cross sectional shape of the conventional resin coated metal pipe is purely circular. In the bench 4 of FIG. 23, since a seat portion A thereof consists of many resin coated metal pipes 1 provided in parallel, a surface of the seat portion is uneven. Since the aligned pipes do not create a flat surface, the seat surface corresponds to upper halves of the aligned pipes. Thus, a disadvantage of this bench 4 is that it is very uncomfortable to sit on. Even if the resin coated metal pipe 1 is used to form a floor for a cattle shed or a back support for a chair, the same disadvantage may exist.
In the flower stand 5 of FIG. 24, an additional board 7 is mounted on a table portion B, because a flowerpot would not rest stably if the flowerpot is directly put on the table portion B formed by the resin coated metal pipes 1. This requires more labor and is expensive because of the additional board 7.
In the draining board 6 of FIG. 25, the resin coated metal pipes 1 are used as crosspieces and a board 8 is positioned thereon to form a floor surface because of the above described disadvantage. It is difficult to tightly adhere the board 8 to the resin coated metal pipes 1 without limiting the usage thereof. Therefore, the board 8 is normally fixed with nails or screws 9 as illustrated in FIG. 26. Thus, the draining board 6, assembled as described above requires much trouble and labor; is expensive to manufacture; and the finished product is not much to look at. In addition, strength and security of the screw fixed portion may be poor, and the life thereof may not be long because it is bitten with water. The water may percolate through the screw fixed portion to the inside of the resin coated metal pipe 1, thereby expanding the bitten area and decreasing the life of the draining board.